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42

T

ROUBLESHOOTING

 C

HART

Symptoms of Abnormal 

Operation (Legacy 

& ComfortNet™ 

Thermostat)

Diagnostic/
Status LED 

Codes

Fault Description

ComfortNet™ 

Thermostat Only

Possible Causes

Corrective Actions

Notes & Cautions

Message

Code

• Furnace fails to operate.

• Integrated control 

module LED display 
provides E7 error code.

• ComfortNet™ 

thermostat “Call 
for Service” icon 
illuminated.

• ComfortNet™ 

thermostat scrolls 
“Check Furnace” 
message.

E7

• Problem with 

igniter circuit.

IGNITER 

FAULT

E7

• Improperly connected 

igniter.

• Shorted igniter.

• Poor unit ground.

• Igniter relay fault on 

integrated control 
module.

• Check and correct 

wiring from integrated 
control module to 
igniter.

• Replace shorted igniter.

• Check and correct unit 

ground wiring.

• Check igniter output 

from control. Replace if 
necessary.

• Turn power OFF 

prior to repair.

• Replace igniter with 

correct replacement 
part.

• Replace control with 

correct replacement 
part.

• Furnace fails to operate 

on high stage; furnace 
operates normally on low 
stage.

• Integrated control module 

LED display provides E8 
error code.

E8

• High stage 

pressure switch 
circuit is closed 
at start of heating 
cycle.

• Induced draft 

blower is 
operating.

• Furnace is 

operating on low 
stage only

PS2 CLOSED

E8

• High stage pressure 

switch contacts sticking.

• Shorts in pressure 

switch circuit wiring.

• Replace high stage 

pressure switch.

• Repair short in wiring

• Turn power OFF prior 

to repair.

• Replace pressure 

switch with proper 
replacement part.

• Furnace fails to operate 

on high stage; furnace 
operates normally on low 
stage.

• Integrated control module 

LED display provides E9 
error code.

E9

• High stage 

pressure switch 
circuit is not 
closed.

• Induced draft 

blower is 
operating.

• Furnace is 

operating on low 
stage only

PS2 OPEN

E9

• Pressure switch hose 

blocked pinched, or 
connected improperly.

• Blocked fue and/or inlet 

air pipe, blocked drain 
system or weak induced 
draft blower.

• Incorrect pressure 

switch set point or 
malfunctioning switch 
contacts.

• Loose or improperly 

connected wiring.

• Inspect pressure switch 

hose. Repair/replace if 
necessary.

• Inspect fue and/or inlet 

air piping for blockage, 
proper length, elbows, 
and termination. Check 
drain system. Correct as 
necessary.

• Check induced draft 

blower performance. 
Correct as necessary.

• Correct pressure switch 

set point or contact 
motion.

• Tighten or correct wiring 

connection.

• Turn power OFF prior 

to repair.

• Replace pressure 

switch with proper 
replacement part.

• Replace induced draft 

blower with proper 
replacement part.

• Furnace fails to operate.

• Integrated control module 

LED display provides EA 
error code.

• ComfortNet™ thermostat 

“Call for Service” icon 
illuminated.

• ComfortNet™ thermostat 

scrolls “Check Furnace” 
message.

EA

• Polarity of 115 volt 

AC is reversed

REVERSED 

PLTY

EA

• Polarity of 115 volt AC 

power to furnace or 
integrated module is 
revered.

• Poor unit ground

• Review wiring diagram to 

correct polarity.

• Verify proper ground. 

Correct if necessary.

• Check and correct 

wiring.

• Turn power OFF prior 

to repair.

• Integrated control 

module LED display EF 
error code.

• ComfortNet™ thermostat 

“Call for Service” .

EF

• Aux switch open

Aux Alarm 

Fault

EF

• High water level in the 

evaporation coil.

• Check overfow pan and 

service.

• Turn power OFF prior 

to service.

• Furnace fails to operate.

• Integrated control module 

LED display provides d0 
error code.

• ComfortNet™ thermostat 

“Call for Service” icon 
illuminated.

• ComfortNet™ thermostat 

scrolls “Check Furnace” 
message.

d0

• Data not yet on 

network.

NO NET 

DATA

d0

• Furnace does not 

contain any shared data.

• Populate shared data 

set using memory card.

• Turn power OFF prior 

to repair

• Use memory card for 

the specifc model.

• Insert memory card 

BEFORE turning 
power ON. Memory 
card may be removed 
after data is loaded 
and power is turned 
off.

• Error code will be 

cleared once data is 

Summary of Contents for DVC8

Page 1: ...ng Most dealers have a list of specific good safety practices follow them The precautions listed in this Installation Manual are intended as supplemental to existing practices However if there is a di...

Page 2: ...ITION 13 CHECK 6 DILUTION AIR 14 CHECK 7 COMPLETE THE INSTALLATION 14 FIX 1 LINER TERMINATION 14 FIX 2 CHANGE VENTING ARRANGEMENTS 14 FIX 3 REBUILD THE CROWN 15 FIX 4 RELINING 15 ELECTRICAL CONNECTION...

Page 3: ...MMUNICATING THERMOSTAT 33 NETWORK TROUBLESHOOTING 34 SYSTEM TROUBLESHOOTING 34 NORMAL SEQUENCE OF OPERATION 34 POWER UP 34 HEATING MODE 35 COOLING MODE 36 FAN ONLY MODE 36 OPERATIONAL CHECKS 36 SAFETY...

Page 4: ...furnace may be used as a construction site heater only if certain conditions are met These conditions are listed in the PRODUCT APPLICATION section of this manual TO PREVENT PERSONAL INJURY OR DEATH D...

Page 5: ...TO EXTREMELY LOW RETURN AIR TEMPERATURES AND EXPOSURE TO CORROSIVE OR VERY DIRTY ATMOSPHERES WARNING TO PREVENT PERSONAL INJURY OR DEATH DUE TO ASPHYXIATION THIS FURNACE MUST BE CATEGORY I VENTED DO N...

Page 6: ...CAUTIONS NOTE Discharge body s static electricity before touching unit An electrostatic discharge can adversely affect electrical com ponents Use the following precautions during furnace installation...

Page 7: ...anual J Load Cal culations published by the Air Conditioning Contractors of America In the USA this furnace MUST be installed in accordance with the latest edition of the ANSI Z223 1 booklet entitled...

Page 8: ...g the furnace Ensure adequate combustion air is available for the furnace Improper or insufficient combustion air can expose building occupants to gas combustion products that could include carbon mon...

Page 9: ...3 Latest Edition Section 1 23 1 The following steps shall be followed with each appliance connected to the venting system placed in operation while any other appliances connected to the venting syste...

Page 10: ...the furnace area by means of ventilation grilles or ducts connecting directly to the outdoors or spaces open to the outdoors such as attics or crawl spaces CATEGORY I VENTING VERTICAL VENTING TO PREV...

Page 11: ...e power to furnace Counterflow units are shipped with the induced draft blower discharging from the top of the furnace Top as viewed for a counterflow installation Vent the furnace in accordance with...

Page 12: ...ghest connected equip ment draft hood outlet or flue collar Wash Clay Tile Size 8 x 8 x12 Each x 24 Length 1 2 to 1 Air Space Second Floor First Floor Attic Floor Roof Line Throat Damper Breech Clean...

Page 13: ...he lowest existing vent connector and examine the inside of the elbow or tee at the base of the liner Asmall amount of soot may be considered acceptable provided the installer vacuums it away If ruste...

Page 14: ...lly with a B Vent Under some conditions a 90 furnace could be installed rather than an 80 furnace The 90 furnace can be vented hori zontally or vertically through PVC pipe Next use a flashlight and sm...

Page 15: ...teel liners were developed for use with oil or solid fuel appliances They are not suitable for use with gas fired appliances Flexible liners specifically intended and tested for gas applications are l...

Page 16: ...val or routine maintenance JUNCTION BOX RELOCATION EDGES OF SHEET METAL HOLES MAY BE SHARP USE GLOVES AS A PRECAUTION WHEN REMOVING HOLE PLUGS WARNING Line voltage connections can be made through eith...

Page 17: ...facilitate use with most cooling equipment Consult the wiring diagram located on the blower compartment door for further details of 115 Volt and 24 Volt wiring NOTE For single stage cooling applicati...

Page 18: ...HUM TRIM ENABLE Move to the ON position to enable dehumidification ON OFF S5 FOSSIL FUEL APPLICATIONS This furnace can be used in conjunction with a heat pump in a fossil fuel application A fossil fue...

Page 19: ...feeding one of the HUM terminals with a field installed wire from the R terminal or by connecting to the NO side of the low fire pressure switch AUXILIARY ALARM SWITCH The control is equipped with a 2...

Page 20: ...TO ENSURE SAFE AND PROPER FURNACE OPERATION ALL CONVERSIONS MUST BE PERFORMED BY A QUALIFIED INSTALLER OR SERVICE AGENCY This unit is configured for natural gas The appropriate manufacturer s propane...

Page 21: ...with masonry plaster or insulation or subjected to repeated wetting by liquids such as water except rain water detergents or sewage Gas line entrance Right side gas entrance alternate General Furnace...

Page 22: ...propane gas pressure must be 10 inch WC at the furnace manifold with all gas appliances in operation Maintaining proper gas pressure depends on three main factors 1 Vaporization rate depending on tem...

Page 23: ...at or cool position When the furnace is installed without a cooling coil it is rec ommended that a removable access panel be provided in the outlet air duct This opening shall be accessible when the f...

Page 24: ...EDURE AND ADJUSTMENT Furnace must have a 115 VAC power supply properly connected and grounded Proper polarity must be maintained for correct operation In addition to the following start up and adjustm...

Page 25: ...Ft until high capacity 100 is achieved Once achieved the display will show Ft without flashing A 5 minute timer will be started to al low sufficient opportunity for the gas pressure to be tested 5 If...

Page 26: ...10 0 w c Propane Gas Minimum 11 0 w c Maximum 13 0 w c INLET GAS SUPPLY PRESSURE If supply pressure differs from table make the necessary ad justments to pressure regulator gas piping size etc and or...

Page 27: ...cubic foot sec ft3 of gas being delivered to the furnace If the dial is a one cubic foot dial divide the number of seconds recorded in step 2 by one If the dial is a two cubic foot dial divide the num...

Page 28: ...ing 4 individual dip switches The following number refers to the individual labeled dip switch within that section Model Tap Low Stage High Stage Low Stage High Stage Cool Cool Heat Heat A 520 800 121...

Page 29: ...cooling air flow determined in step 2 and find the required cooling speed and adjustment setting Example A MVC80604BX furnace installed with a 2 5 ton air conditioning system The air flow needed is 10...

Page 30: ...demands are managed differently in a fully communi cating system than they are in a non communicating wired system The system operating mode as determined by the thermostat determines which unit calcu...

Page 31: ...thaComfortNet com patible heat pump in a fossil fuel application Afossil fuel applica tion refers to a combined gas furnace and heat pump installation which uses an outdoor temperature sensor to deter...

Page 32: ...ge AC ComfortNet G W1 W2 Y1 Y2 O 1 2 R C 4 Position Connectors from CTK0 Thermostat Kit System Wiring between Furnace and Non Communicating CompatibleSingleStageAirConditioner COMFORTNET SYSTEM ADVANC...

Page 33: ...difiable Model Number MOD NUM Displays the furnace model number Serial Number SER NUM Displays the furnace serial number Optional Software SOFTWARE Displays the application software revision IDENTIFIC...

Page 34: ...wards ground and when data 1 is decreasing towards ground data 2 is increasing towards 5V Typically the data 1 line is approximately 2 6Vdc and the data 2 transmission line is ap proximately 2 3Vdc Th...

Page 35: ...d Rapid Flashing Normal network traffc On Solid Data 1 Data 2 miss wire Possible Cause Corrective Action Comments None None None Communications Failure Depress Learn Button Verify that bus BIAS and TE...

Page 36: ...ontrol module performs safety circuit checks Outdoor fan and compressor are energized to their appropriate speed Circulator blower is energized on the appropriate cool speed at the level and time dete...

Page 37: ...t electrical components Use the following precautions during furnace installation and servicing to protect the integrated control module from dam age By putting the furnace the control and the person...

Page 38: ...ck for blockage and or leakage Check hose connections at and internal to furnace Wiring Check electrical connections for tightness and or corrosion Check wires for damage Filters FILTERS TO ENSURE PRO...

Page 39: ...in cleanout cable Attach a variable speed reversible drill to the other end of the cable Slowly rotate the cable with the drill and insert it into one of the heat exchanger tubes While reversing the d...

Page 40: ...Call for Service icon illuminated ComfortNet thermostat scrolls Check Furnace message E0 Furnace lockout due to an excessive number of ignition retries 3 total LOCKOUT E0 Failure to establish fame Ca...

Page 41: ...rs and ductwork for blockage Clean flters or remove obstruction Check circulator blower speed and performance Correct speed or replace blower motor if necessary Check burners for proper alignment Chec...

Page 42: ...d improperly Blocked fue and or inlet air pipe blocked drain system or weak induced draft blower Incorrect pressure switch set point or malfunctioning switch contacts Loose or improperly connected wir...

Page 43: ...ontrol module has lost communications with circulator blower motor MOTOR COMM b1 Loose wiring connection at circulator motor control leads Failed circulator blower motor Failed integrated control modu...

Page 44: ...t scrolls Check Furnace message b7 MOTOR PARAMS b7 Furnace operates at reduced performance or Integrated control module LED display provides b9 error code b9 LOW ID AIRFLOW B9 Blocked filters Restrict...

Page 45: ...D 115 VAC POLARITY DATANOT YET ON NETWORK INVALID MEMORYCARD DATA BLOWER MOTOR NOT RUNNING BLOWER COMMUNICATION ERROR BLOWER HP MIS MATCH BLOWER MOTOR OPERATING IN POWER TEMPERATURE OR SPEED LIMIT BLO...

Page 46: ...D Set dip switches S3 1 and S3 2 to the appropriate ON OFF positions 2 Select model and desired High Stage Heating Airflow Determine the corresponding tap A B C or D Set dip switches S4 3 and S4 4 to...

Page 47: ...D On On Add 5 Off Off Minus 5 On Off Add 10 Off On Minus 10 On On A Off Off B On Off C Off On D On On A Off Off B On Off C Off On D On On Disabled Off Enabled On Disabled Off Enabled On 25 Off Off 50...

Page 48: ...PU 3 IF ANY OF THE ORIGINAL WIRE AS SUPPLIED WITH THE FURNACE MUST BE REPLACED IT MUST BE REPLACED WITH WIRING MATERIAL HAVING A TEMPERATURE RATING OF C USE COPPER CONDUCTORS ONLY RD INTEGRATED CONTR...

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